Frozen espresso cheesecake

1 1 / 2 cups finely ground chocolate wafer cookies (8 ounces; about 35 cookies)

4 tablespoons unsalted butter, melted

1 / 2 cup plus 2 tablespoons sugar

4 large egg yolks, room temperature

4 1/ 2 teaspoons good-quality instant espresso powder (such as Medaglia dâ€™Oro)

Pinch of salt

1 1/ 2 pounds mascarpone cheese, room temperature

1 1 / 2 teaspoons pure vanilla extract

12 ounces hard torrone (Italian nougat), cut into 1 / 4 -inch pieces

1 / 2 cup heavy cream, chilled

Stir together the cookie crumbs, melted butter, and 3 tablespoons sugar in a medium bowl; set aside.
Put the egg yolks, 1 / 4 cup sugar, the espresso, and salt in the heatproof bowl of an electric mixer. Set the bowl over a pan of simmering water; whisk until thick, about 2 minutes. Transfer the bowl to an electric mixer fitted with the whisk attachment; beat on medium speed 2 minutes. Stir in the mascarpone and vanilla by hand until smooth. Stir in the torrone; set aside.
Beat the cream with the remaining 3 tablespoons sugar in a clean mixing bowl until soft peaks form. Fold the whipped cream with a rubber spatula into mascarpone mixture. Refrigerate.
Line a 10x5x3-inch loaf pan with plastic wrap and parchment paper, leaving an overhang on the sides. Pour one-third of the mascarpone mixture into the lined pan; even the layer with an offset spatula. Evenly top with half of the crumb mixture; press the crumbs gently. Repeat to make a second layer of mascarpone mixture and crumbs. Top with the remaining mascarpone mixture. Loosely fold over the parchment and plastic wrap. Freeze at least 3 hours, or overnight.
To serve, let the cake stand at room temperature 10 minutes. Set the loaf pan in a larger pan; pour cold water into the pan to reach three-quarters up the sides of the loaf pan. Let stand 10 seconds. Holding the parchment, lift out the cake. Invert onto a plate; peel off the plastic and parchment. Let stand 10 minutes more before serving.

MAKES ONE 1 0 Ã— 5 - INCH CAKE ;

SERVES 10